Biochem 2.2 : Protein Structure Levels

The linear sequence of amino acids in a protein, linked by peptide bonds. This sequence is determined by the gene encoding the protein.

A chain of two or more amino acids linked by peptide bonds.

A peptide with more than 10 amino acids.

A polypeptide with more than 50 amino acids.

The covalent bond formed between two amino acids when the carboxyl group of one amino acid reacts with the amino group of another.

The average weight of an amino acid residue in a protein, calculated by considering the proportions and molecular weights of different amino acids.

The change in the amino acid sequence of a protein, often caused by mutations in the gene.

The order of amino acids in a polypeptide chain.

The three-dimensional arrangement of amino acid residues in a protein, including interactions like hydrogen bonds between backbone groups, that define its local shape.

The overall three-dimensional shape of a protein, formed by interactions between side chains of amino acids.

The arrangement of multiple polypeptide chains in a protein complex.

In proteins, the ability of the primary sequence to determine the higher levels of structure, such as secondary, tertiary, and quaternary structures.

A common secondary structure in proteins, characterized by a helical coil stabilized by hydrogen bonds between backbone groups.

Another common secondary structure in proteins, formed by sheets of polypeptide strands connected by hydrogen bonds between backbone groups.

The process where proteins fold into a specific three-dimensional shape, driven by the interactions between amino acid residues.

The ability of a protein to maintain its specific three-dimensional structure, which is essential for its function.

Regions in proteins where the polypeptide chain sharply turns back on itself, often involving glycine and/or proline residues.

Amino acid known for its flexibility, often found in β-turns due to its lack of a side chain.

The layout of β-strands next to each other in a β-sheet where the C-terminal end of one strand is aligned with the N-terminal end of the adjacent strand.

The layout of β-strands next to each other in a β-sheet where the C-terminal ends of adjacent strands are aligned.

The ability of a protein to interact with specific molecules based on its unique shape.

A weak, non-covalent interaction that contributes to protein stability. It occurs between polar neutral groups, like threonine and glutamine.

A strong, covalent bond that stabilizes tertiary protein structure. They form between sulfur atoms in cysteine residues.

A type of non-covalent interaction that stabilizes the tertiary structure. It occurs between oppositely charged ionic groups, like lysine and aspartate.

A type of non-covalent interaction that stabilizes tertiary structure, involving one ionic group and one polar neutral group, like arginine and serine.

A type of secondary protein structure characterized by a tightly coiled, helical arrangement of the polypeptide chain, stabilized by hydrogen bonds between backbone amide and carbonyl groups.

An amino acid with a small side chain that allows for greater flexibility in the polypeptide backbone, making it less suitable for α-helix formation.

An amino acid with a rigid cyclic structure, disrupting the regular hydrogen bonding pattern found in α-helices, making it unfavorable for α-helix formation.

A type of secondary protein structure composed of multiple polypeptide chains (β-strands) arranged side-by-side, stabilized by hydrogen bonds between backbone amide and carbonyl groups of adjacent strands.

β-turns are important for:

The sequence of amino acids within a polypeptide chain that determines its three-dimensional structure and function.

The interactions and arrangements of the polypeptide chain within a protein, including α-helices, β-sheets, and random coils.